1. Field of the Invention
The present invention relates to a wind turbine rotor blade constituting a wind-generating wind turbine, and to the wind-generating wind turbine.
2. Description of Related Art
As a wind turbine rotor blade, one disclosed in WO2008/086805A2 is known for example.
In recent years, there is proposed a wind turbine rotor blade 100 having a super cap structure which satisfies both lightweight requirement and strength requirement as shown in FIG. 6. The wind turbine rotor blade 100 includes a later-described outer skin material 11, leading edge sandwich materials 12, super cap materials (main strength materials) 13, trailing edge sandwich materials 14 and sheer webs (crossbeam materials) 15.
The leading edge sandwich materials 12 and the trailing edge sandwich materials 14 have a sandwich structure in which the outer skin material 11 and the inner skin material 17 form a skin material, and a resin foam body such as PVC and wood material such as balsa form a core material.
In FIG. 6, a symbol 16 represents an adhesive 16 which connects (couples) the super cap materials 13 and the sheer webs 15 to each other.
If a safety factor of a buckling strength and safety factors of material strengths (tensile strength and strength against compression) of members constituting the wind turbine rotor blade 100 (specifically the outer skin material 11, the leading edge sandwich material 12, the super cap material 13, the trailing edge sandwich material 14 and the sheer web 15) can substantially be set equal to each other (e.g., 2), it is possible to further reduce the weight of the wind turbine rotor blade.
According to the wind turbine rotor blade 100 shown in FIG. 6, however, there is an adverse possibility that the super cap material 13 is buckled by a load in a flap direction (longitudinal direction: vertical direction in FIG. 6) before the wind turbine rotor blade 100 exerts 100% material strength, the trailing edge sandwich material 14 and/or a back side and/or front side of the outer skin material 11 located closer to a trailing edge 18 than a trailing edge end of the trailing edge sandwich material 14 is buckled by a load in an edge direction (directions of a leading edge and a trailing edge: direction perpendicular to the flap direction).
To increase a buckling strength of the super cap material 13 against a load in the flap direction, a cross-sectional area of the super cap material 13 is maintained constant, a width of the super cap material 13 (length in a cord direction (lateral direction in FIG. 6)) is reduced, a thickness of the super cap material 13 is increased, and an interval between the sheer webs 15 (distance between the sheer web 15 located on the side of the leading edge and the sheer web 15 located on the side of the trailing edge) is reduced.
However, there is a problem that a width of the trailing edge sandwich material 14 (length in the cord direction (lateral direction in FIG. 6)) is increased, and the buckling strength of the trailing edge sandwich material 14 against a load in an edge direction is further deteriorated.